1. Field of the Invention
This invention relates in general to lawn mowers and, in particular, to riding lawn mowers having a cutter assembly between the front and rear wheels of the mower. More specifically, but without restriction to the particular embodiment hereinafter described in accordance with the best mode of practice, this invention relates to a vehicle frame and an articulateable pantograph mechanism for lifting a mower cutter assembly above the center of the wheels of a riding lawn mower.
2. Discussion of the Related Art
The art of riding lawn mowers having a cutter assembly positioned between the front and rear wheels, has been contributed to by a number of prior riding movers. These include, for example, the mowers disclosed in U.S. Pat. No. 3,550,364 which issued to O. Musgrave on Dec. 29, 1970 and U.S. Pat. No. 4,679,382 issued to Saruhashi et al. Jul. 14, 1987. The riding mowers disclosed in these patents typify prior riding lawn mowers which include a frame or chassis, rear and front wheel assemblies, a drive motor commonly engaged with the rear wheel assembly to provide drive power thereto, a steering mechanism linked to the front wheel assembly, an operator's seat to place an operator of the mower within easy reach of the mower's controls, and lastly, a cutter assembly located between the front and rear wheel assemblies.
There have been proposed various prior lifting mechanisms for moving the cutter assembly from an extended position for cutting the lawn over which the mower is driven to a fully lifted or retracted position. The cutter assembly is typically retracted when the mower is driven from one cutting area to another. The retracted cutter assembly is thus positioned to avoid hitting obstacles as the mower is driven from one location to another. Such obstacles typically include, for example, curbs when the mower is being employed to cut lawn on island or median sections in a landscaped area including parking lots. Similar variations in ground level are encountered in municipal use of lawn mowers along roadsides and in park or camping areas.
One ever present design consideration in the manufacturing of riding lawn mowers, is vehicle stability. Generally, as the frame and wheel axles are positioned lower to the ground, vehicle stability increases. This design consideration is in conflict with the objective of retracting the cutter assembly as high as possible above ground level. Prior riding lawn mowers, as exemplified by those discussed above, have handled this problem by providing the mower frame with relatively large wheels and a retracting mechanism that lifts the cutter assembly to a height approximately level with the wheel axles. These riding lawn mowers thus sacrifice vehicle stability for cutter assembly clearance. Prior hereto, there has not been proposed a low profile riding lawn mower including relatively small wheels while proving maximum cutter assembly clearance.